Detection of Immunoglobulin G Antibodies toNeospora caninumin Humans: High Seropositivity Rates in Patients Who Are Infected by Human Immunodeficiency Virus or Have Neurological Disorders

Abstract

Considering that little is known about the epidemiology of Neospora caninum infection in humans, particularly in populations with high Toxoplasma gondii infection rates, the present study aimed to investigate the presence of antibodies to N. caninum in T. gondii-seropositive and -seronegative individuals. A total of 256 serum samples divided into four groups (61 samples from human immunodeficiency virus [HIV]-positive patients, 50 samples from patients with neurological disorders, 91 samples from newborns, and 54 samples from healthy subjects) were assessed for N. caninum and T. gondii serologies by indirect fluorescent-antibody test, enzyme-linked immunosorbent assay, and immunoblotting (IB). Immunoglobulin G antibodies to N. caninum were predominantly detected in HIV-infected patients (38%) and patients with neurological disorders (18%), while newborns and healthy subjects showed lower seropositivity rates (5% and 6%, respectively). Seropositivity to N. caninum was significantly associated with seropositivity to T. gondii in both HIV-infected patients and patients with neurological disorders. Seroreactivity to N. caninum was confirmed by IB, with positive sera predominantly recognizing the 29-kDa antigen of N. caninum. The results of this study indicate the presence of N. caninum infection or exposure in humans, particularly in HIV-infected patients or patients with neurological disorders, who could have opportunistic and concurrent infections with T. gondii. These findings may bring a new concern for the unstable clinical health of HIV-infected patients and the actual role of N. caninum infection in immunocompromised patients.

Serological detection of Toxoplasma gondii, Leishmania infantum and Neospora caninum in cats from an area endemic for leishmaniasis in Brazil

“…The importance of N. caninum as a zoonotic agent remains unknown, but N. caninum antibodies have been detected in humans in the United States (TRANAS et al, 1999) and Brazil (LOBATO et al, 2006;BENETTI et al, 2009). In Brazil, IgG antibodies against N. caninum were detected in patients infected with human immunodeficiency virus (HIV) and in patients with neurological disorders, suggesting the possibility that neosporosis could be an opportunistic parasite in immunocompromised patients (LOBATO et al, 2006).…”

“…In Brazil, IgG antibodies against N. caninum were detected in patients infected with human immunodeficiency virus (HIV) and in patients with neurological disorders, suggesting the possibility that neosporosis could be an opportunistic parasite in immunocompromised patients (LOBATO et al, 2006). Furthermore, the authors found a positive correlation between infections by N. caninum and T. gondii, and suggested that further studies are needed to evaluate N. caninum infections in humans.…”

All about neosporosis in Brazil

“…In MG, serum samples from HIV-infected patients (Group I), patients with neurological disorders (Group II), newborns (Group III) and a healthy control (Group IV) by IFAT (1:50) were assayed for N. caninum antibodies by indirect ELISA to detect immunoglobulin G (IgG), utilizing soluble antigen and IB as a confirmatory test, with lysed tachyzoites as antigen (LOBATO et al, 2006). They found IB positive patients in all groups, and HIV-infected patients and those with neurological disorders patients presented significantly higher prevalence.…”

Ocorrência e fatores de risco associados às infecções por Toxoplasma gondii e Neospora caninum em cães no município de Natal, Estado do Rio Grande do Norte, Nordeste do Brasil

“…Para N. caninum, existem evidências sorológicas em seres humanos, no entanto, não foram descritos relatos comprovados da doença. Por outro lado, tal possibilidade não pode ser descartada (TRANAS et al, 1999;LOBATO et al, 2006).…”